The Happy Thread III

[Nerdanel]

Originally Posted by sisterandcousinandaunt

Sounds good.

How DO they determine it? Is it temperature dependent, like alligators? Or is this about how the scientists determine it, lol.

Hehe.. Mostly the scientists, yes.

As far as I know and understand (the articles I read weren't the most fresh ones..), it's not determined by environmental factors, so temperature doesn't seem to play a role.. The thing is, they can switch. Sex cells are differentiated from undifferentiated cells that seem to be able to differentiate into more or less any cell type. When the hydra enters gametogenesis, though, all stem cells become sex cells, and within one individual they are pre-determined. "Male" sex cells can switch to female, though, but not the other way around. Then there are all kinds of cool mechanisms by which this is controlled so that not all individuals become completely female. Many species are hermaphrodites, too.
Anyway, even as adults they can switch their sex. Which is pretty cool, and has also been found in some fish.

And all of this makes me awfully happy.